Pressure controlled valve



May 19, 1931.

J. LE VALLEY PRESSURE. CONTROLLED VALVE Filed Jan. 14, 1928 INVENTOR.

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H15 ATTRNEY J0 BY Patented May 19, 1931 UNITED STATES PATENT OFFICE JOHIN' LE VALLEY, OF PAINTED POST, NEW YORK, ASSTGNOR TO INGERSOLL-RAND COMPANY, OF JERSEY CITY, JERSEY, A. CORPORATION OF NEW JERSEY PRESSURE CONTROLLED VALVE Application filed January 14, 1928. Serial No. 246,792.

This invention relates to pressure controlled valves and more particularly that type of valve which is adapted to be opened by the pressure of motive fluid at a critical maximum pressure and closed upon decrease of the pressure of motive fluid to a predetermined minimum.

The invention is a modification of the type of valve disclosed in J. H. Castle and W. D. Rogers, No. 1,138,278'of May 4, 1915, and

its object is to enable the valve to be closed and opened more positively. v

The type of valve herein described is of general application, but is of special value in connection with regulating systems for air or other gas compressors whereby the pressure'is partially or completely unloaded upon the increase of its discharge pressure to a predetermined maximum and reloading of the compressor upon decrease of its discharge to a predetermined minimum.

The invention accordingly, relates to certain features of construction in combination which contribute to more positive action of the. valve at the critical pressures as are pointed out in the following specification and the appended claim.

Other objects and advantages will be in part obvious and in part pointed out hereinafter.

The drawing shows in vertical longitudinal section a valve constructed in accordance with the practice of the invention and associated with a compressor provided with unloading mechanism.

Referring to the drawing, the invention is shown in combination with a compressor comprising a cylinder A havin a reciprocating iston B and suitable bac and front 40 heads 6 and D respectively. The discharge from the compressor is adapted to pass out through suitable check valves E into a discharge chamber F and thence through a pipe G to a reservoir H of any suitable construction. The air or other gas to be compressed extent within the cylinder A. The spiders controlled valve comprising a valve chest Q is drawn into the cylinder A through an inlet chamber J provided with inlet valves K which are adapted to be actuated automatically by pressure diflerential. In this instance the loading and unloading of the cylinder is accomplished by a pair of spiders L which are adapted to press the inlet valves K from their seats, thereby preventing pressure from accumulating to any material L are actuated by the compressed air from:

the reservoir H introduced into unloader cylinders 0 within which are provided plungers P preferably formed integrally with the spiders L. v

The invention provides means for supply-V ing compressed air to the unloader cylinders 0 when the discharge pressure exceeds a predetermined maximum in the reservoir H and for discharging the compressed air from the cylinders 0 when the pressure in the reser- 'voir H drops below a predetermined minimum.

To this end there is provided a pressure having an inlet opening R and an exhaust opening S preferably in alignment with each other and provided with valve seats T and U respectively. A cylindrical bore V con nects the two seats T and U and forms a guide for a cylindrical valve W movable in the bore and adapted at its ends to close the valve seats T and U respectively preventin the flow of motive fluid through the bore 6 to the discharge seat U. The valve W is in the form of a plug having peripheral guiding surfaces W and W adjacent its upper and lower ends respectively which cooperate slidably with the wall of the bore V to maintain the ends of the valve in substantial alignment With the valve seats T and U. The discharge seat U may be adjustable longitudinally with respect to the inlet passage seat T to vary the travel of the valve for extending or reducing the range in pressure between 90 the maximum and minimum receiver pressures at which the valve is intended to act. To this end the valve chest Q is provided with a threaded bore X of relativeiiy large diameter to receive a hollow plug having at its inner end the seat U. The seats T and U are preferably heldin the relative positions to which they may be adjusted by suitable shims Z inserted between a shoulder b and the end of the valve chest body Q. Intermediate the seats T and U there is provided a-port a which is adapted to be connected by means of a bushing d and the cylinders ,O and to convey motive fluid such as compressed air from the reservoir H to the unloader cylinders.

If the valve W is oflt' its seat T compressed air is adapted to flow through restricted openings w in the valve W and preferably in its outer surface part way along its length to the port 0. Normally the valve W-is held to its seat T by means of a plunger 7 pressed by means of a spring 9 against the valve W with a pressure exceeding that pressure to which the valve W is exposed at the inlet opening R. Tensioning of the spring g is eflected by means of a plug h hollowed to receive the spring 9 and threaded into the plug b, the plug h being held in position by a jamb charge opening nut 7'. The spring 9 is adapted to bear against a collar is on the plunger f. The. plunger f is adapted to extend through the end of the plu h there being provided a bore 0 of slig tly larger size than the plunger to permit the restricted escape of air from the dis S to atmosphere. Y In this instance the valve W is hollow for i 1 art of its length as at p to receive the end of the plunger f and a bearing block q is provided to prevent excessive wear of the point of the plunger against the valve W.

The discharge of compressed-air from the pipe 6 is accomplished through a by-pass passage leading from the port 0 to a chamber 8 adjacent the discharge passage seat U.

. The compressed air isconducted to the inlet passage B through a pipe 25 leading from thedischarge reservoir H to a chamber a in the valve chest Q adjacent the inlet opening B there being a suitable pipe bushing/v provided threaded into the chamber u.

In operation normally the valve W is held to its seat T closing the inlet opening R by the pressure of the spring -gholding the plunger f against the valve W. The pressure area on the end of the valve W is substan-' tially the area of the inlet opening-R since any air leaking by the seat T finds its way to atmosphere through the restricted openlugs 10, the port a, the bypass passage r 'andvthe discharge opening S to atmosphere through the bore 0. If the'pressure exceeds a predetermined maximum in the reservoir H the pressure of the spring 9 is overcome stricted opening 'w into the piping e to the unloader pressing the valve W from its seat, thereby increasing the pressure area of the end of the valve and causing the valveto be accel erated to close the discharge seat U. Compressedair then finds its way past the report 0 and thence to the unloader cylinders O. The plungers P cause the spiders-L to lift thevalves K from their seats, thereby unloading the compressor.

The valve seat U is made larger than the valve seat T so that when the valve W is held against the seat U the pressure area against which the pressure of the motive fluid acts is greater than the pressure area which is substantially the area ofthe inlet opening R which causes the initial actuation of the valve W. r

If the pressure in the reservoir- H drops below a predetermined minimum the tension of the seat U startmg the valve W from its seat U. Due tothe and the restriction of the bore 0 the compressed air stored up in the pipe 6 and the cylinders 0 assists the spring 9 to snap the valve W to its seat T. Likewise any compressed air passing the restricted openings w in the valve W assists in maintaining the throwin pressure effective against thelower end oft e valve "W. The by-pass passage r' is larger than the combined area of the restricted openings to to permit the compressed air to be discharged past the seat U more readily than it enters at the openings w.

Because the area of the seat U' is larger than the area of'the inlet seat T the, valve W is held positively in its open position to per- Thus by plished, among others, before referred to.

I claim:

A pressure controlled valve comprising a valve chest having an inlet opening therein, a port in the valve chest for supplying pressure fluid to an element intended to be controlled, a bore in the valve chest having a seat at one end, a hollow plug threaded into the valve chest and having a valve seat arranged coaxially with the bore, an outlet opening in the plug, a valve in the form of a plug movable in said bore and cooperating with the first said seat to prevent the flow of the above construction are accomthe ob ects hereinpressure fluid through said bore to the outlet large area of the seat U valve is moved more quickly 1 and eflectivelyvto the inlet seat T.

said port to the seat in the plug and shims openings in said valve to convey pressure fluid from said inlet opening to the port, a by-pass passage of large area as compared to said restricted openings and leading from In testimony whereof I have signed this specification.

JOHN LE VALLEY. 

